MIAMI -- For any tape-measure-minded Miami Marlin, a three-digit sign hangs above the center field seats, advertising the distance from home plate as 502 feet.

It's a sign of trouble.

Eager to show how far they can hit the ball in their new park, the Marlins are hardly hitting at all.

They began the season confident they had assembled a contending club to christen their home. They ended the month last in the NL East with an 8-14 record, and anemic offense was the primary culprit.

One theory holds that the spacious ballpark has messed up the Marlins' talented hitters, because they're trying too hard for homers. Forget trying to hit the 502 sign -- the distance to the outfield fence is daunting enough at 386 feet in left-center, 418 in center and 392 in right-center.

"It's too big, in my opinion. It's huge," said Diamondbacks manager Kirk Gibson, whose team just concluded a four-game series against the Marlins in the new ballpark.

"They'll have to figure out how to hit in it," he said. "You tend to want to pull the ball more in a big park, because that's where the ball goes out. That's the way they built it, and they'll have to deal with it."

On Monday, the Marlins trailed 7-0 before they finally scored against Patrick Corbin, who won in his big league debut. The Marlins totaled 73 runs during April, which tied for second-worst in the majors.

Miami's .228 batting average and .291 on-base percentage also ranked near the bottom, surprising for a lineup that features a balance of power and speed, two recent NL batting champions and a precocious slugger.

Perhaps mercifully, the Marlins began a nine-game trip Tuesday in San Francisco. Manager Ozzie Guillen threatened to make "a very drastic change" and complained his hitters are reluctant to alter their approach.

"This game is about adjustments, and we're not making any adjustments," Guillen said. "Day in and day out you see the same swings, the same approach at the plate, the same mistakes. People survive in this game and have better careers if they can make an adjustment quick. If you cannot make an adjustment, I will make it for you."

Is Marlins Park part of the problem?

"If they don't want to hit here, call your agent and get traded," Guillen said. "I don't see any problem with the other team. They're kicking our butts pretty good. If that's in your head, please tell me, and we'll find somebody who isn't worried about the ballpark."

The Marlins have actually played better at home than on the road, where they began the week with a 2-9 record and .202 batting average. But they were bad enough in their two most recent home games to draw boos, a worrisome development just as attendance is on the upswing.

Crowds exceeded 30,000 in eight of the first 11 home games. But to keep fans coming back, the Marlins must win.

"There's no honeymoon," team president David Samson said. "We need the team to play better, and they know it. There are no excuses. It was a bad April, but it's time for May."

Disappointing performances in the first month extended beyond hitting. The defense has been shaky, and ace Josh Johnson and new closer Heath Bell are each 0-3. But aside from Johnson, each starter has an ERA below 3.35.

Meanwhile, only Omar Infante and Logan Morrison have been swinging the bat well. Hanley Ramirez is hitting .207 after a recent 0-for-26 slump, and 22-year-old slugger Giancarlo Stanton has one home run after hitting 34 homers last year.

Sluggers aren't the only ones struggling to make the most of the dimensions at Marlins Park. Jose Reyes (.220) and Emilio Bonifacio (.244) have slumped at the top of the order even though their game is to get on base.

The roomy outfield should be inviting targets for the two speedsters, but Reyes has only eight extra-base hits, and Bonifacio has none.

"I'm not able to use the gaps here yet," Reyes said, "but it's coming soon."

Reyes has seen things like this before. When the New York Mets first moved into roomy Citi Field in 2009, several of their star hitters had trouble, too. This year, those fences were moved in and the walls were lowered.

With so much focus on the size of the Miami ballpark, there's already talk about moving in the fences. Marlins hitters have activated the animated home-run sculpture nine times, but they've also hit a lot of flyouts to the warning track.

Not only is the outfield vast, but so far the ball doesn't carry as well as at the Marlins' former home.

"We're going to have to deal with it," said catcher John Buck, who was batting .200. "The only thing we can control is our approach -- just put the ball in play a little more consistently, and not worry about the field or the dimensions, because they're obviously not going to change this year."